With some of Verizon's enterprise customers about to lose their cloud service for up to two days, now is the time for them to prepare for the extended downtime.

"One of the major selling points of cloud computing is that it takes the burden of IT management off the shoulders of the customer, but with this outage, Verizon's customers are right back in the thick of things when it comes to IT management," said Dan Olds, an analyst with The Gabriel Consulting Group. "They're going to have to figure out how to minimize the impact of the Verizon two-day fail on their business."

Verizon confirmed to Computerworld this week that it will shut down its Verizon Cloud service to do maintenance for up to two days, starting at 1 a.m. ET Saturday. Users are being told to shut down their virtual machines at least an hour ahead of time.

That means users of Verizon Cloud about 10% of the company's enterprise cloud users won't be able to access their cloud-based email, apps or stored data. That's significant for businesses that increasingly depend on the cloud to keep their systems and their businesses running. Users are known to complain about outages that last for minutes or hours.

A shutdown that could last two days shocked analysts, who have said it will be difficult for Verizon to compete as an-enterprise ready cloud provider if their maintenance takes users offline for days.

"Honestly, [users] should threaten to pull their business," said Rob Enderle, an analyst with the Enderle Group. "If this looks like it will be a recurring problem, I'd recommend changing vendors. In today's world, there should be no legitimate reason for a shutdown this long if the service is set up correctly."

Verizon did not answer questions about what the service maintenance entails, but Olds said a company representative told him that it's an upgrade to the system that should "virtually eliminate future planned downtime."

Whatever the reason for the downtime, corporate IT shops still need to prepare.

The first step for enterprise customers is to figure out exactly what they have in the Verizon Cloud.

"While this may sound easy, many customers are going to be surprised at the array of applications and data that are hosted with Verizon," said Olds. "Then they need to evaluate the impact of the two-day outage on the enterprise. They can probably do without some services or data sets for a few days, but others are more important, and some are possibly mission critical."

Some customers should quickly try to find a short-term solution -- possibly from Amazon, Google or another cloud vendor -- to host their important apps. Others should download their mission critical data in case something goes wrong with Verizon's upgrade.

Olds noted that since Verizon Cloud came out of beta in the third quarter of 2014, a lot of users will still be in the "tire kicking" stage and won't be as significantly affected as users who have a lot of mission critical apps and data in the cloud service.

To limit potential headaches, companies should be sure employees and work groups clearly understand what's coming this weekend, said Charles King, an analyst with Pund-IT.

If users know what's coming, they can access necessary files and documents before the Saturday morning shutdown and plan for any potential communication issues.

"That doesn't mean an emergency won't arise," King said. "In fact, in the 24/365 global business model so many companies follow these days, something's bound to happen over the weekend. It would be wise for organizations to create contingency plans to deal with problems, including distributing alternative contact information, including personal phone numbers and email addresses."

Copyright 2016 IDG Communications. ABN 14 001 592 650. All rights reserved. Reproduction in whole or in part in any form or medium without express written permission of IDG Communications is prohibited.